diff --git a/Objects/unicodeobject.c b/Objects/unicodeobject.c
index fe0337fc46e..501921df8ee 100644
--- a/Objects/unicodeobject.c
+++ b/Objects/unicodeobject.c
@@ -11180,10 +11180,14 @@ unicode_index(PyObject *self, PyObject *args)
                                             &start, &end))
         return NULL;
 
-    if (PyUnicode_READY(self) == -1)
+    if (PyUnicode_READY(self) == -1) {
+        Py_DECREF(substring);
         return NULL;
-    if (PyUnicode_READY(substring) == -1)
+    }
+    if (PyUnicode_READY(substring) == -1) {
+        Py_DECREF(substring);
         return NULL;
+    }
 
     result = any_find_slice(1, self, substring, start, end);